The present invention concerns the field of digital communication and pertains particularly to extraction of a clock signal from a received transmission signal.
A cordless telephone system generally includes a fixed part, which connects a telephone network to one or more base stations. Base stations are generally connected to a fixed part by wires, or may be integrated directly with the fixed part. The base station communicates with one or more portable parts, typically a handset, via a radio frequency (RF) signal link. For example, the RF signal link may utilize a time division multiple access-time division duplex (TDMA-TDD) signaling system as set out in European Telecommunication Standard (ETS) 300 175-2, European Telecommunications Standards Institute (ETSI), Reference DE/RES-3001-2, October 1992.
A transmission clock signal is included in the RF signals transmitted between the base station and the fixed part. Various circuitry may be used to extract the clock signal. However this task is complicated by RF signal degradation caused, for example, by interference, noise, fading, etc. It is desirable, therefore, to develop circuitry which efficiently and effectively extracts the correct clock signal from a potentially degraded RF signal.